Adjustable spring loading device for relay armatures



Feb; 9, 1943. r, A, TERJESEN 2,310,754

ADJUSTABLE SPRING LOADING DEVICE FOR RELAY ARMATURES Filed May 7, 1940 1-1.9 /////////////4 4 j, 1,, I2n I 1,5557%.- JE/fef A. 7506 72 Patented Feb. 9, 1943 ADJUSTABLE SPRING LOADING DEVICE FOR RELAY ARMATURES Tellef A. Terjesen, Hoboken, N. 3., assignor to Signal Engineering & Manufacturing Company, New York, N. Y., a corporation of Massachusetts Appiication May '7, 1940, serial No. 333,876

2 Claims.

The present invention relates to electrical circuit controllers of the type commonly known as relays, and has for its object to provide an improved device for regulating the loading of a spring employed for maintaining the pivoted armature of a relay in its retracted or nonoperating position, with respect to the magnetic core.

In the operation of electrical relays provided with pivotally mounted armatures, it is desirable to be able to closely regulate the retractive force exerted on an armature, in order to meet varying circuit conditions under which the relay may be utilized, as regards voltage and pull-up current. The device of the present invention is particularly characterized by the provision of an improved spring loading arrangement for the armature, whereby the spring pressure may be varied from substantially zero to almost any desired amount, Within the limits of the relay design.

The above and other advantageous feature of the invention will hereafter more fully appear from the following description with reference to the accompanying drawing, in which:

Fig. 1 is a view in side elevation of a relay provided with a spring loading device embodying the invention.

Fig. 2 is a view in front elevation of the relay shown in Fig. 1.

Fig. 3 is a fragmentary view, showing parts of the spring loading device on an enlarged scale.

Fig. 4 is a fragmentary view in front elevation of the parts shown in Fig. 3.

Figs. 5 and 6 are perspective views of separate parts of the device shown in Fig. 3.

Referring first to Figs. 1 and 2, the invention is shown, for purposes of illustration, as being embodied in an electrical circuit controller of the relay type, the essential elements of which comprise an insulating base I carrying a U-shaped magnetic core 2, one leg of which is surrounded by an energizing winding 3. magnetic armature l is pivotally supported on the lower end of the other core leg, by means of a pivot 5 extending between the arms 6 of a saddle, carried by the core 2. In the normal deenergized condition of the winding 3, the armature 4 occupies the position of Fig. 1, wherein a contact arm 1 is out of engagement with a stationary contact 8 on the base I, and the present invention contemplates the provision of means for variably loading the armature A to control upward movement thereof in response to energization of the winding 3.

As best shown in Figs. 3 and 4, the pivot 5 extends beyond the saddle on each side, and a slot 9 is provided in each end thereof. A coil spring Iii surrounds each extended pivot portion, with one end of the spring received in the slot 9 and its other end bearing on a pressure pin H projecting from the side of the armature 4. Thus the springs i0 exert a force tending to hold the armature A retracted, with the winding 3 in its deenergized condition. The bottom of the saddle 6 provides a stop l2 to determine the lowermost position of the armature 4, or a back contact 8a can be provided, as indicated in dotted lines in Fig. 1.

Each end of the pivot 5 carries a worm gear 13 adjacent the spring slot 9, the gear l3 being turnable with the pivot 5, and the teeth of this gear are in mesh with a worm it. As best shown in Figs. 5 and 6, the worm I i provides cylindrical seats [5 on each side thereof, which are adapted to be engaged by the turned-over arms l6 of a clip I? mounted on the pivot 5 between the worm gear i3 and the saddle arm 6. Therefore, the clip [7 serves to hold the Worm l4 and worm gear [3 in mesh, to prevent turning of the pivot 5, and maintain any particular adjustment of the spring It with respect to the armature 4.

With the arrangement of parts described thus far, it is obvious that the ends of the springs I0 bearing on the armature pins H, maintain a balanced load on the armature, opposing its pull-up when attracted by that portion of the core 2 carrying the energizing winding 3, and the mounting of each spring provides for a very delicate adjustment of this loading. To this end, the worm I4 provides an angular adjusting head 18 having a tool receiving slot IQ, whereby the worm l4 may be turned in its clip 11. Such turning of the worm M will impart rotation to the worm gear 13 in one direction or the other, to either increase or decrease the tension of the spring [U as exerted on the pin H of th armature. That is to say, the spring I 0 can be wound either more or less tightly by turning the pivot 5 through its worm gear l3, by reason of the reception of the end of the spring in the slot 9.

As shown in Fig. 5, the head l8 of the worm M is flat on all sides, and the norrhal tension of the spring It! is such as to yieldingly maintain one of these flat sides against a stop pin 26 projecting from the side of the saddle arm 6. Therefore, the combined action of the clip I! holding the worm and worm gear in mesh, and the pressure of the flat head 18 against the pin 20, insures that any given adjustment of the spring 10 will be continuously maintained. However, when a screw driver is inserted in the slot I9, and the head l8 turned, the entire assembly as mounted on the clip 11, will yield slightly away from the pin 20, to permit turning of the worm M the desired amount. With this arrangement, each complete revolution of the worm I4 is divided into a number of equal steps, each represented by the engagement of a flat surface of the head [8 with the stop pin 20. The net result is a micrometer-like adjustment of the spring loading on the armature, ranging from substantially zero up to almost any desired amount, in order to meet the operating requirements of the circuit in which the relay is employed. Thus, by means of the above described adjustment, the relay can be set to pull up in response to diiferent voltages and different values of operating current. g

In assembling the parts, it is unnecessary to use any screws or brackets attached to the relay structure, since all parts of the device are mounted on the pivot 5. This ease of assembly is due to the fact that when the clip I1 is mounted on the pivot 5, its arms l6 hold the worm 14 in mesh with the worm gear l3, so that the act of assembly prevents the parts from becoming disengaged, without necessitating the use of any tools. Furthermore, with the spring l once engaged with the armature pin H, its tension serves to hold the angular head iii of the worm M in engagement with the stop pin 20, so that the device cannot get out of adjustment, due to turning of the worm M as the result of ordinary vibrations to which the relay may be subjected.

From the foregoing, itis apparent that by the present invention there is provided an improved spring loading device for relay armatures, by means of which the degree of spring loading may be varied through a wide range with extreme accuracy, to meet the conditions of the circuit in which the relay is to be employed. It is to be noted that the armature is entirely free of the weight of any of the parts of the loading device, so that the retractive force acting on the armature is due entirely to its own weight and the pressure of the springs acting on the armature.

The use of two loading springs, one on each side of the armature, insures even wear of the armature bearing, and also provides a safety factor, due to the fact that one spring would function if the other should break.

I claim:

1. A spring loading device for relay armatures, comprising in combination a stationary frame supporting a pivot on which an armature is freely mounted, with said pivot providing a portion extending on the opposite side of said frame with respect to said armature, a stop carried by said frame adjacent the extended portion of said pivot, a coil spring surrounding the extended portion of said pivot and connected at its ends to said pivot and said armature, and means comprising a worm and gear assembly mounted on said pivot for causing relative angular movement between said pivot and armature, and adjustment of the pressure exerted by said spring on said armature, with the tension of said spring serving to maintain the worm and gear assembly against said stop, to prevent turning of said pivot on its axis following an adjustment of the spring pressure.

2. A spring loading device for relay armatures, comprising in combination a stationary frame supporting a pivot on which an armature is freely mounted, with said pivot providing a portion extending on the opposite side of said frame with respect to said armature, a stop carried by said frame adjacent the extended portion of said pivot, a coil spring surrounding the extended portion of said pivot and connected at its ends to said pivot and said armature, and means comprising a worm and gear assembly mounted on said pivot for causing relative angular movement between said pivot and armature, with the tension of said spring serving to maintain the worm against said stop to prevent turning of said pivot on its axis, and with said assembly being yieldable away from the stop to permit turning of said worm and gear and adjustment of the pressure exerted by the spring on said armature.

TELLEF A. TERJESEN. 

